One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,6,7)(3,5,4,8)(9,10,13,14)(11,12,15,16)(17,18,20,22)(19,23,24,21)(26,27)(28,35)(29,37)(39,40)(2,7)(5,8)(10,14)(12,16)(25,26,30,27)(28,33,35,31)(29,34,37,32)(36,39,38,40)(1,3,6,4)(2,5,7,8)(9,10,13,14)(11,12,15,16)(25,27,30,26)(28,33,35,31)(29,34,37,32)(36,40,38,39)(1,4,6,3)(2,5,7,8)(9,11)(10,12)(13,15)(14,16)(17,19,20,24)(18,21,22,23)(25,28,30,35)(26,31,27,33)(29,38,37,36)(32,40,34,39)(1,5)(2,4)(3,7)(6,8)(9,12)(10,15)(11,14)(13,16)(25,29,30,37)(26,32,27,34)(28,36,35,38)(31,39,33,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.